Eddy current testing apparatus and related methods

Abstract

An eddy current testing apparatus and related methods for conducting non-destructive examination of heat exchanger tubes accessible via a heat exchanger tubesheet. The apparatus comprises a motor-driven drive pulley and one or more idler pulleys engageable with the test cable of the test probe to feed out or retract the cable and test head which are insertable into the heat exchanger tube under test. A support bracket of the apparatus includes manually-expandable tube clamps operated by an actuating lever. The clamps include a tubular securement sleeve with expandable portion for insertion into and releasably locking to an anchoring tube in tubesheet. This supports the apparatus from the tubesheet in a cantilevered manner. The idler pulley(s) may be mounted to a pivot arm movable between an inward position to press the cable into engagement with the drive pulley, and an outward position which releases the cable to facilitate setup or takedown.

1 . An eddy current testing apparatus comprising:
 a bracket configured for detachable coupling to a tubesheet of a heat exchanger;   a rotatable drive pulley operably coupled to a motor supported by the bracket;   a pivot arm coupled to the bracket and pivotably movable about a pivot axis, the idler pulley comprising a first idler pulley;   an eddy current test probe comprising a test head and cable, the cable routed between and engageable with the first idler pulley and the drive pulley;   the first idler pulley operable to press the test cable against the drive pulley to maintain engagement therebetween;   wherein rotating the drive pulley in a first rotational direction feeds out cable from the apparatus, and rotating the drive pulley in a second rotational direction retracts cable back to the apparatus.   
     
     
         2 . The apparatus according to  claim 1 , wherein the bracket comprises a face plate defining a test probe feed opening which slideably receives the test head and cable therethrough from the drive pulley for insertion into a first tube under test of the tubesheet. 
     
     
         3 . The apparatus according to  claim 2 , further comprising a replaceable alignment ferrule removably coupled to the face plate through the test probe feed opening, the alignment ferrule being engageable with the first tube when the face plate is positioned proximate to the tubesheet. 
     
     
         4 . The apparatus according to  claim 3 , wherein the alignment ferrule has an annular body comprising a central passage which defines the probe feed opening which is sized to pass the test head and cable therethrough. 
     
     
         5 . The apparatus according to  claim 4 , wherein the alignment ferrule has a two-piece structure comprising a rear piece coupled to a front piece through the test probe feed opening in the face plate. 
     
     
         6 . The apparatus according to  claim 3 , wherein the alignment ferrule comprises a tapered frustoconical portion which is partially insertable into and engageable with an open end of the first tube in the tubesheet to center the test head in the first tube. 
     
     
         7 . The apparatus according to  claim 2 , further comprising a pair of tube clamps detachably coupled to the face plate, the tube clamps including a tubular securement sleeve including a radially expandable portion insertable into a respective second heat exchanger tube and a third heat exchanger tube in the tubesheet for anchoring the bracket thereto. 
     
     
         8 . The apparatus according to  claim 7 , wherein each securement sleeve includes a radially expandable end operable to frictionally engage inside surfaces of the second or third heat exchanger tubes to secure the bracket thereto. 
     
     
         9 . The apparatus according to  claim 8 , wherein the expandable ends of each securement sleeve comprises a plurality of circumferentially spaced apart slots orientated along a length the securement sleeve. 
     
     
         10 . The apparatus according to  claim 8 , wherein each tube clamp includes an operating rod extending through the securement sleeve, and an expansion plug coupled proximate to a first end of the operating rod and engageable with the expandable end of the securement sleeve, the expansion plug being configured to radially spread the expandable ends of each securement sleeve radially outwards to frictionally engage the inside surfaces of the second or third heat exchanger tubes. 
     
     
         11 . The apparatus according to  claim 10 , wherein the expansion plug includes an inner portion inserted inside the expandable end of the securement sleeve, and a diametrically enlarged outer portion disposed outside the expandable end including an outside diameter larger than an inside diameter of the expandable end. 
     
     
         12 . The apparatus according to  claim 11 , wherein the tube clamps each comprise a manually-operated actuating lever pivotably coupled to a second end of the operating rod. 
     
     
         13 . The apparatus according to  claim 12 , wherein the actuating lever of each tube clamp is pivotably movable between: (i) a locked position which draws the operating rod and expansion plug towards the actuating lever and into the securement sleeve to spread the expandable end of the securement sleeve radially outwards to frictionally lock the tube clamp to the second or third heat exchanger tubes; and (ii) an unlocked position which projects the operating rod and expansion plug away from the actuating lever and the expandable end of the securement sleeve to allow the expandable end to collapse radially inward to unlock the tube clamp from the second or third heat exchanger tubes. 
     
     
         14 . The apparatus according to  claim 10 , wherein the tube clamps support the bracket from the tubesheet in a cantilevered manner when the actuating levers are in the locked position. 
     
     
         15 . The apparatus according to  claim 14 , wherein each operating rod extends through an elongated adjustment slot in the face plate which allows tube clamp to be adjusted in position relative to the face plate. 
     
     
         16 . The apparatus according to  claim 1 , wherein the pivot arm is movable between an inward engaged position in which the first idler pulley presses the test cable of the test probe against the drive pulley, and an outward disengaged position which releases the test cable from the drive pulley. 
     
     
         17 . The apparatus according to  claim 16 , further comprising a return spring which biases the pivot arm towards the inward engaged position. 
     
     
         18 . The apparatus according to  claim 1 , further comprising a second idler pulley rotatably coupled to the pivot arm, the second idler pulley arranged and operable to press the test cable of the test probe against the drive pulley at a different location than the first pulley. 
     
     
         19 . The apparatus according to  claim 18 , wherein the first and second idler pulleys are operable to maintain about 90 degrees of contact between the drive pulley and the cable 
     
     
         20 . The apparatus according to  claim 19 , wherein the second idler pulley is disposed on top of the drive pulley and the first idler pulley is disposed on one side of the drive pulley. 
     
     
         21 . The apparatus according to  claim 18 , wherein the drive pulley and the first and second idler pulleys are: (a) oriented inline and parallel to each other, and (b) oriented perpendicular to the face plate which is parallel to the tubesheet when the bracket is coupled to the tubesheet. 
     
     
         22 . The apparatus according to  claim 18 , wherein the pivot arm has an L-shape. 
     
     
         23 . The apparatus according to  claim 1 , wherein a first end of the pivot arm is coupled to the bracket via a pivot pin which defines the pivot axis, and a second end of the pivot arm is not coupled to the bracket to define a handle for manually moving the pivot arm about the pivot axis between the inward engaged position and the outward disengaged position. 
     
     
         24 . The according to  claim 1 , further comprising a programmable controller operably coupled to the motor and test probe, the controller operable to rotate the drive pulley in the first and second rotational directions via the motor. 
     
     
         25 - 40 . (canceled)